Proximity services, i.e. services discovering users or discovering customers or discovering points of sale or the like, that share the same or similar interests in the vicinity of a mobile device are promising services for customers using such mobile devices. In a wireless communication network, i.e. a public land mobile network, typically a number of base stations or base transceiver stations support communication for a number of user equipments or mobile devices. Such user equipments communicate with the base transceiver station via a downlink and via an uplink connection. The downlink connection refers to the communication link (or to the direction) from the base transceiver station to the user equipment, and the uplink connection refers to the communication link (or to the direction) from the user equipment to the base transceiver station. Furthermore, user equipments or mobile devices are known that are additionally able to communicate directly with other user equipments in geographical vicinity, which is also called device to device communication or peer to peer communication.
Proximity discovery can be achieved by various radio technologies today. These methods rely on continuous or intermediate radio scans and/or transmissions of signals of the user equipment, allowing to detect other users or other customers in geographical proximity of, e.g., 10 to 50 meters, preferably 30 meters, i.e. other user equipments (either being mobile devices or being fixedly installed devices), which are also interested in proximity services. The conventional method (for such user equipments able to communicate with other user equipments via a peer to peer communication link) has the drawback that radio scans and transmissions are required even in case that there is no other user/customer or user equipment at all within the proximity discovery range. This process is strongly draining the batteries of battery-powered user equipments since the transmitters need to be switched on to broadcast information, especially in order to indicate the interest and/or the presence of the user equipment being prepared to engage in proximity services communication. Additionally, such transmissions of radio frequency signals from the user equipments conducting proximity discovery lead to additional interference within the vicinity of such user equipments, which is a considerable drawback and which reduces at least potentially the overall service level of mobile communications both for the user equipment concerned but also for other user equipments. This drawback is all the more important in that such proximity discovery radio frequency signals are even transmitted by user equipments in case that there are no other user equipments or customers or share points at all in the vicinity of the user equipment that emits the proximity discovery radio signals.